As daughter of the former demon lord, Mio's foster parents were slain by powerful demons after her life. Still seeking to slay her, Basara reveals himself as a member of the hero clan--an enemy of the demons--and vows to protect Mio as a member of his family.
The Master-Servant testament
 is predicated on mutual trust.
Das Meister-Diener-Testament
 basiert auf gegenseitigem Vertrauen.
El pacto entre maestro y siervo se basa 
en la premisa de la confianza mutua.
El pacto entre maestro y siervo se basa 
en la premisa de la confianza mutua.
Le pacte d’allégeance suppose
une confiance mutuelle.
Il contratto Servo-Padrone 
è basato sulla fiducia reciproca.
O pacto entre Mestre e Servo é consolidado
 no conceito da confiança mutual.
Договор господин-слуга работает 
на взаимном доверии.